U.S. patent number 4,319,499 [Application Number 05/927,690] was granted by the patent office on 1982-03-16 for lubricating device for final drive gearing of power transmission unit.
This patent grant is currently assigned to Toyota Jidosha Kogyo Kabushiki Kaisha. Invention is credited to Yoshio Sanui, Kaoru Wakahara, Yasuyoshi Yasui.
United States Patent |
4,319,499 |
Sanui , et al. |
March 16, 1982 |
Lubricating device for final drive gearing of power transmission
unit
Abstract
In a final drive gearing of a power transmission unit, which
comprises a drive pinion shaft supported by a pair of axially
spaced bearings carried on an upright partition wall of a
trans-axle casing and including a pinion in mesh with a crown
wheel, an abdominal cavity is provided on the partition wall to
receive lubrication oil dipped up by rotation of the crown wheel,
and a lateral hole is provided through the partition wall to
communicate the cavity into an annular space around the drive
pinion shaft between the bearings.
Inventors: |
Sanui; Yoshio (Okazaki,
JP), Wakahara; Kaoru (Toyota, JP), Yasui;
Yasuyoshi (Toyota, JP) |
Assignee: |
Toyota Jidosha Kogyo Kabushiki
Kaisha (Aichi, JP)
|
Family
ID: |
14896825 |
Appl.
No.: |
05/927,690 |
Filed: |
July 25, 1978 |
Foreign Application Priority Data
|
|
|
|
|
Oct 18, 1977 [JP] |
|
|
52-124898 |
|
Current U.S.
Class: |
475/200;
184/11.1; 184/6.12; 475/159; 74/467; 74/606R |
Current CPC
Class: |
F16C
33/6666 (20130101); F16H 3/0915 (20130101); F16H
57/0421 (20130101); F16H 57/0483 (20130101); F16H
48/08 (20130101); Y10T 74/2186 (20150115); F16H
2048/423 (20130101); F16C 2361/61 (20130101); Y10T
74/19991 (20150115) |
Current International
Class: |
F16H
57/04 (20060101); F16H 057/04 (); F16H 057/02 ();
F16H 037/08 (); F01M 001/00 () |
Field of
Search: |
;74/700,424,467,66R,66A,710,713,15.63 ;184/11R,6.12 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1042394 |
|
Oct 1958 |
|
DE |
|
1912368 |
|
Nov 1969 |
|
DE |
|
2654717 |
|
Jun 1977 |
|
DE |
|
2020198 |
|
Jul 1970 |
|
FR |
|
1124697 |
|
Aug 1968 |
|
GB |
|
1182747 |
|
Mar 1970 |
|
GB |
|
1188863 |
|
Apr 1970 |
|
GB |
|
1403730 |
|
Aug 1975 |
|
GB |
|
1482116 |
|
Aug 1977 |
|
GB |
|
Primary Examiner: Husar; C. J.
Assistant Examiner: Gotts; Lawrence J.
Attorney, Agent or Firm: Armstrong, Nikaido, Marmelstein
& Kubovcik
Claims
What is claimed is:
1. In a power transmission unit for a motor vehicle of the
front-engine, front-wheel drive type comprising:
a trans-axle casing for connection at its upright front seating
face to a cylinder block of an engine and at its upright rear
seating face to a transmission casing for change-speed gearing
means, said trans-axle casing having an upper compartment for
containing a disengageable coupling for connection to a crankshaft
of said engine and a lower compartment, the lower compartment being
provided with an upright partition wall to subdivide the
compartment into front and rear chambers; and
a final drive gearing means and a differential gear means located
within the lower compartment, said final drive gearing means
including a drive pinion shaft supported along the fore-and-aft
axis of said vehicle by a pair of axially spaced tapered roller
bearings carried on said partition wall and a drive pinion integral
with said drive pinion shaft and located within the front chamber,
said drive pinion shaft being coaxially connected to said
change-speed gearing means in the rear chamber, and said
differential gear means being arranged in front of said drive
pinion and including a crown wheel driven by said pinion, said
crown wheel being positioned on one side of the longitudinal axis
of said drive pinion shaft;
the improvement wherein said partition wall includes a passage
means formed therein on the same side of said drive pinion shaft
axis as said crown wheel such that lubricating oil picked up by
rotation of said crown wheel is directly supplied via said passage
means into an annular space around said drive pinion shaft between
said bearings for lubricating said bearings, and wherein said
partition wall further includes an aperture, at the bottom portion
thereof, interconnecting the front and rear chambers, said aperture
being located on the opposite side of said drive pinion shaft axis
from said crown wheel to prevent the lubricating oil from directly
flowing into the rear chamber from the front chamber during
rotation of said crown wheel.
2. A power transmission unit as set forth in claim 1, wherein said
passage means includes a lateral hole passing through said casing
and said partition wall and into said annular space, and plug means
for sealing said lateral hole passing through said casing.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to a power transmission
unit for motor vehicles, and more particularly to a power
transmission unit of the type which comprises a trans-axle casing
rigidly secured at its upright front seating face to a cylinder
block of an engine and having an upper compartment to contain
therein a disengageable coupling for connection to a crankshaft of
the engine and a lower compartment to contain therein a final drive
gearing and a differential gear unit, and a transmission casing
sealingly jointed at its upright front seating face to the upright
rear seating face of the trans-axle casing to contain therein a
change-speed gearing drivingly connected to an output shaft of the
disengageable coupling, and in which the trans-axle casing is
provided therein with an upright partition wall to subdivide the
lower compartment into front and rear chambers, and the final drive
gearing includes a drive pinion shaft supported by a pair of
axially spaced bearings carried on the partition wall and a drive
pinion integral with the drive pinion shaft located within the
front chamber, the drive pinion shaft being coaxially connected to
the change-speed gearing, and the drive pinion being meshed with a
crown wheel to drive the differential gear unit.
In such a final drive gearing of the type as described above, the
bearing facing to the front chamber is directly splashed with
lubrication oil dipped up by rotation of the crown wheel, but the
bearing facing to the rear chamber may not be splashed with the
dipped up lubrication oil. It is, therefore, necessary to
positively lubricate the latter bearing so as to ensure durability
of the power transmission unit.
SUMMARY OF THE INVENTION
Accordingly, it is a primary object of the present invention to
provide an improved power transmission unit in which both bearings
for the drive pinion shaft are sufficiently lubricated by
lubrication oil dipped up by rotation of the crown wheel, and which
is relatively simple in structure and is economical to
manufacture.
In the preferred embodiment of the present invention, the primary
object is accomplished by providing a power transmission unit
wherein an abdominal cavity is provided on the upright partition
wall of the trans-axle casing and arranged adjacent the drive
pinion shaft to receive therein lubrication oil dipped up by
rotation of the crown wheel, and a lateral hole is provided through
the partition wall to communicate the cavity into an annular space
around the drive pinion shaft between the bearings.
BRIEF DESCRIPTION OF THE DRAWINGS
Additional objects and advantages of the present invention will be
more readily apparent from the following detailed description of a
preferred embodiment therefore when taken together with the
accompanying drawings in which:
FIG. 1 is a schematic side view of a motor vehicle equipped with a
power transmission unit in accordance with the present
invention;
FIG. 2 is an enlarged sectional view of the transmission unit of
FIG. 1;
FIG. 3 is an enlarged sectional view of a final drive gearing shown
in FIG. 2;
FIG. 4 is an enlarged horizontal sectional view of the final drive
gearing shown in FIG. 2; and
FIG. 5 is an enlarged front view showing an upright partition wall
of the trans-axle casing of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, in particular to FIG. 1, there is
illustrated a power transmission unit which is mounted on a motor
vehicle 10 of the type of front-engine and front-wheel drive. A
housing assembly 20 for the transmission unit comprises a
trans-axle casing 21 and a transmission casing 22 which are
fluid-tightly jointed to each other by way of an upright
intermediate plate 23. The trans-axle casing 21 is rigidly secured
at its upright front seating face to an upright rear seating face
of a cylinder block of an engine 11 and, as well shown in FIG. 2,
is configured generally to conform with a friction clutch 12
contained in the upper compartment thereof and with a final drive
gearing 40 and a differential gear unit 13 contained in the lower
compartment thereof. The lower compartment of the trans-axle casing
21 is sealingly closed by a dome-shaped cover plate 24 to retain
lubrication oil within the housing assembly 20.
The transmission casing 22 is fluid-tightly secured at its upright
front seating face to the upright rear seating face of the
trans-axle casing 21 by way of the intermediate plate 23 and is
configured generally to comform with a change-speed gearing 30
contained therein. The change-speed gearing 30 is drivingly
connected at one hand thereof to the crankshaft of engine 11
through the friction clutch 12 and connected at the other hand
thereof to the differential gear unit 13 through the final drive
gearing 40. In addition, an extension housing 25 is fluid-tightly
secured to the rear end seating face of the transmission casing 22
to complete the housing assembly 20.
The friction clutch 12 has a power input member for connection to
the crankshaft of engine 11 and a power output member 12a supported
by a pair of axially spaced bearings B.sub.1 and B.sub.2
respectively from the intermediate plate 23 and from the
transmission casing 22. The power output member 12a is formed with
a driving gear 12b located between the bearings B.sub.1 and B.sub.2
and is further surrounded by a seal member to keep foreign matter
out of the casing 22 and to retain lubrication oil within the
casing 22. An idler shaft 31 is supported by a pair of axially
spaced bearings B.sub.3 and B.sub.4 respectively from the
intermediate plate 23 and from the transmission casing 22 and is
also formed with an idler gear 31a and a reverse driving gear 31b.
The idler gear 31a is permanently meshed with the driving gear 12b
on the power output member 12a, and the reverse driving gear 31b is
axially spaced from the idler gear 31a and adjacent the right-hand
bearing B.sub.4.
The change-speed gearing 30 includes an output mainshaft 32 which
is supported by a pair of axially spaced bearings B.sub.5 and
B.sub.6 respectively carried on the intermediate plate 23 and the
transmission housing 22. The mainshaft 32 is provided thereon with
an input gear or fourth gear 32d which meshes with the idler gear
31a of the idler shaft 31 and with a gear 33d integral with a
counter-shaft 33. The counter-shaft 33 is also formed integral with
the three further gears 33a, 33b and 33c of differing sizes which
are meshed respectively with first, second and third gears 32a, 32b
and 32c journalled on the mainshaft 32. The selection of gear
ratios is effected by a gear-shift mechanism 14 (See FIG. 1) which
is operatively connected through a mechanical linkage 14b to a pair
of synchronizers 32e and 32f.
When the first synchronizer 32e is in its neutral position, the
first and second gears 32a, 32b are free from the mainshaft 32. The
synchronizer 32e acts in the usual manner to establish synchronism
in a driving connection between the mainshaft 32 and the first gear
32a or the second gear 32b, depending upon which direction the
synchronizer 32e is shifted by an unshown first shift-fork of the
gear-shift mechanism 14. When the second synchronizer 32f is in its
neutral position, the third gear 32c and fourth gear 32d are free
from the mainshaft 32. The synchronizer 32f acts in the usual
manner to establish synchronism in a driving connection between the
mainshaft 32 and the third gear 32c or the fourth gear 32d,
depending upon which direction the synchronizer 32f is shifted by
an unshown second shift-fork of the gear-shift mechanism 14.
A reverse gear 32g is formed integral with the second synchronizer
32f and is arranged to be in a common vertical plane with the
reverse driving gear 31b when the synchronizer 32f is in its
neutral position. If an unshown reverse idler gear is shifted by an
unshown thrid shift-fork of the gear-shift mechanism 14 under the
neutral condition of the synchronizer 32f, the reverse idler gear
is brought into engagement with the gears 31b and 32g to establish
a reverse torque delivery path between the clutch output member 12a
and the mainshaft 32.
The counter-shaft 33 is supported by a pair of axially spaced
bearings B.sub.7 and B.sub.8 respectively from the intermediate
plate 23 and the transmission casing 22 and is located
substantially at the same height above the ground level as the
mainshaft 32 and in parallel with the same. In FIG. 2, the
counter-shaft 33 is, however, illustrated at a position lower than
the mainshaft 32 to clearly depict the meshing engagement of the
gear transmission.
As well seen in FIGS. 2 to 4, the final drive gearing 40 has a
drive pinion shaft 41 coaxially connected to the mainshaft 32 by
means of a spline coupling 49, and the trans-axle casing 21 is
provided therein with an upright partition wall 21A subdividing the
lower compartment into front and rear chambers R.sub.1 and R.sub.2.
The drive pinion shaft 41 is arranged along the fore-and-aft axis
of the vehicle and is supported by a pair of axially spaced tapered
roller bearings 43 and 44 carried on a bearing boss 21a of the
upright partition wall 21A. A hypoid drive pinion 41a is formed
integral with the drive pinion shaft 41 and is meshed with a hypoid
crown wheel 42 within the front chamber R.sub.1. As shown in FIG.
4, the hypoid crown wheel 42 is secured to a differential casing
13a of unit 13 by bolts 45 and is rotated by the drive pinion 41a
in a counterclockwise direction, as shown in FIG. 3.
Hereinafter a lubricating device 50 in accordance with the present
invention will be described in detail, particularly in reference to
FIGS. 4 and 5. The lubricating device 50 comprises an abdominal
cavity 51 opening toward the interior of the front chamber R.sub.1
and a lateral hole 52 communicating the cavity 51 into an annular
space 53 around the drive pinion shaft 41. The cavity 51 is
arranged at the same side of the drive pinion shaft as the crown
wheel 42 to receive lubrication oil dipped up by rotation of the
crown wheel, and the lateral hole 52 serves to induct the
lubrication oil from the bottom of cavity 51 into the annular space
53 thereby to lubricate both tapered roller bearings 43 and 44. The
cavity 51 is formed in the casting process of the trans-axle casing
21, and the lateral hole is formed substantially in a horizontal
direction by drilling through the housing wall and is sealingly
closed by a plug 59. Furthermore, the upright partition wall 21A is
provided at its bottom portion with an axial through hole 21b
communicating the front chamber R.sub.1 into the rear chamber
R.sub.2. The through hole 21b is provided at the opposite side of
the drive pinion shaft to the crown wheel 42. In addition, a
predetermined amount of lubrication oil is stored within the bottom
of the housing assembly 20 to dip therein lower portions of the
crown wheel 42, the gears on the mainshaft 32, and the gears on the
counter-shaft 33. In FIGS. 2 and 3, dot and dash lines indicate a
liquid surface of the lubrication oil during operation of the
transmission unit, and two dots and dash lines indicate a liquid
surface of the lubrication oil under inoperative condition of the
transmission unit.
In operation, assuming that a selected one of forward speed ratios
in the change-speed gearing 30 is established by operation of the
gear-shift mechanism 14, rotation torque from the engine 11 is
conveyed to the driving gear 12b by way of the friction clutch 12
and then transmitted to the counter-shaft 33 by way of the idler
gear 31a and fourth gear 32d. When the counter-shaft 33 is rotated,
the first, second and third gears on the mainshaft 32 are rotated
by engagement with the gears 33a, 33b and 33c on the counter-shaft
33 in such a manner that the mainshaft 32 is driven under the
selected forward speed ratio. The rotation torque of mainshaft 32
is transmitted to the drive pinion shaft 41 through the spline
coupling 49 and, in turn, the crown wheel 42 is rotated in a
counterclockwise or forward direction by engagement with the drive
pinion 41a on the shaft 41 to drive a pair of wheel axles 15.
Then, the lubrication oil is stirred up by rotation of the
respective gears on the mainshaft 32 and the countershaft 33 and is
also dipped up by rotation of the crown wheel 42 in the front
chamber R.sub.1, as shown by arrows in FIG. 3. Thus, the dipped-up
lubrication oil directly splashes onto the tapered roller bearing
43 and flows into the cavity 51 of partition wall 21A, as shown in
FIG. 4. Further, the lubrication oil in cavity 51 flows into the
annular space 53 through lateral hole 52 to lubricate both the
tapered roller bearings 43 and 44. Then, the lubrication oil
passing through the bearing 43 returns into the front chamber
R.sub.1, while the lubrication oil passing through the bearing 44
flows into the rear chamber R.sub.2 and returns into the front
chamber R.sub.1 through the communication hole 21b.
When the reverse torque delivery path is established by operation
of the gear-shift mechanism 14, the reverse driving gear 31b is
coupled with the reverse gear 32g by way of the reverse idler gear
to rotate the mainshaft 32 in a reverse direction. This results in
clockwise rotation of the crown wheel 42 in front chamber R.sub.1.
In this instance, the lubrication oil in front chamber R.sub.1 is
dipped up by the clockwise rotation of the crown wheel 42 and flows
around the same. Then, the lubrication oil partly flows into the
cavity 51 to lubricate the tapered roller bearings 43 and 44. Other
operation under the reverse drive is substantially the same as that
under the above-noted forward drive.
Although the lubricating device 50 of the embodiment includes the
cavity 51 opening toward front chamber R.sub.1 and the lateral hole
52 communicating the bottom of cavity 51 into the annular space 53,
it should be noted that various modifications may be made without
departing from the spirit of the present invention and the scope of
the appended claims. Furthermore, it will be noted that the present
invention may be adapted to a motor vehicle of the type of
rear-engine and rear-wheel drive.
* * * * *